sentence in passive voice. Rohit did not slap Kunal.

Explanation

The sentence is in the simple past tense:
Rohit did not slap Kunal.
To change it into the passive voice:
Object Kunal becomes the subject.
did not + verb changes to was not + past participle.
"Kunal was not slapped by Rohit."
Kunal was not slapped by Rohit. – Correct
Kunal had not been slapped by Rohit. – Past perfect tense
Kunal was not being slapped by Rohit. – Past continuous tense
Kunal has not been slapped by Rohit. – Present perfect tense
Correct Answer: Kunal was not slapped by Rohit.